In Universal Mobile Telecommunications System (UMTS) wireless communication networks, trace sessions for mobile stations are activating using International Mobile Subscriber Identifiers (IMSI) for the subscribers. In Long Term Evolution (LTE) and 4G wireless telecommunication networks that includes Evolved UMTS Terrestrial Radio Access Network (E-UTRAN), however, the International Mobile Subscriber Identifier (IMSI) is not used in the access stratum signaling messages in E-UTRAN. Because of the differences between UMTS and LTE, the trace session can not be activated directly in E-UTRAN using IMSI information.
One proposal uses an interface between LTE element managers (EM). In particular, the proposal suggests using a long training field in a peer-to-peer interface that is between the element manager of an eNodeB and the element manager of a mobility management entity (MME). This interface and connection are used to forward the IMSI as a part of trace session request to the relevant MME. This solution, however, requires the long training field and the peer-to-peer interface between the relevant element managers, but these are not required by LTE.
It is therefore needed to have a trace session activated in LTE from the EM of E-UTRAN that can use a subscriber's IMSI.
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